Public Health Actions to Control Measles Among Afghan Evacuees During Operation Allies Welcome - United States, September-November 2021

On August 29, 2021, the United States government oversaw the emergent establishment of Operation Allies Welcome (OAW), led by the U.S. Department of Homeland Security (DHS) and implemented by the U.S. Department of Defense (DoD) and U.S. Department of State (DoS), to safely resettle U.S. citizens and Afghan nationals from Afghanistan to the United States. Evacuees were temporarily housed at several overseas locations in Europe and Asia* before being transported via military and charter flights through two U.S. international airports, and onward to eight U.S. military bases,† with hotel A used for isolation and quarantine of persons with or exposed to certain infectious diseases.§ On August 30, CDC issued an Epi-X notice encouraging public health officials to maintain vigilance for measles among Afghan evacuees because of an ongoing measles outbreak in Afghanistan (25,988 clinical cases reported nationwide during January-November 2021) (1) and low routine measles vaccination coverage (66% and 43% for the first and second doses, respectively, in 2020) (2).

Trends in Disease Severity and Health Care Utilization During the Early Omicron Variant Period Compared with Previous SARS-CoV-2 High Transmission Periods - United States, December 2020-January 2022

The B.1.1.529 (Omicron) variant of SARS-CoV-2, the virus that causes COVID-19, was first clinically identified in the United States on December 1, 2021, and spread rapidly. By late December, it became the predominant strain, and by January 15, 2022, it represented 99.5% of sequenced specimens in the United States* (1). The Omicron variant has been shown to be more transmissible and less virulent than previously circulating variants (2,3). To better understand the severity of disease and health care utilization associated with the emergence of the Omicron variant in the United States, CDC examined data from three surveillance systems and a large health care database to assess multiple indicators across three high-COVID-19 transmission periods: December 1, 2020-February 28, 2021 (winter 2020-21); July 15-October 31, 2021 (SARS-CoV-2 B.1.617.2 [Delta] predominance); and December 19, 2021-January 15, 2022 (Omicron predominance). The highest daily 7-day moving average to date of cases (798,976 daily cases during January 9-15, 2022), emergency department (ED) visits (48,238), and admissions (21,586) were reported during the Omicron period, however, the highest daily 7-day moving average of deaths (1,854) was lower than during previous periods. During the Omicron period, a maximum of 20.6% of staffed inpatient beds were in use for COVID-19 patients, 3.4 and 7.2 percentage points higher than during the winter 2020-21 and Delta periods, respectively. However, intensive care unit (ICU) bed use did not increase to the same degree: 30.4% of staffed ICU beds were in use for COVID-19 patients during the Omicron period, 0.5 percentage points lower than during the winter 2020-21 period and 1.2 percentage points higher than during the Delta period. The ratio of peak ED visits to cases (event-to-case ratios) (87 per 1,000 cases), hospital admissions (27 per 1,000 cases), and deaths (nine per 1,000 cases [lagged by 3 weeks]) during the Omicron period were lower than those observed during the winter 2020-21 (92, 68, and 16 respectively) and Delta (167, 78, and 13, respectively) periods. Further, among hospitalized COVID-19 patients from 199 U.S. hospitals, the mean length of stay and percentages who were admitted to an ICU, received invasive mechanical ventilation (IMV), and died while in the hospital were lower during the Omicron period than during previous periods. COVID-19 disease severity appears to be lower during the Omicron period than during previous periods of high transmission, likely related to higher vaccination coverage,^† which reduces disease severity (4), lower virulence of the Omicron variant (3,5,6), and infection-acquired immunity (3,7). Although disease severity appears lower with the Omicron variant, the high volume of ED visits and hospitalizations can strain local health care systems in the United States, and the average daily number of deaths remains substantial.^§ This underscores the importance of national emergency preparedness, specifically, hospital surge capacity and the ability to adequately staff local health care systems. In addition, being up to date on vaccination and following other recommended prevention strategies are critical to preventing infections, severe illness, or death from COVID-19.

Exposure science in an age of rapidly changing climate: challenges and opportunities

Climate change is anticipated to alter the production, use, release, and fate of environmental chemicals, likely leading to increased uncertainty in exposure and human health risk predictions. Exposure science provides a key connection between changes in climate and associated health outcomes. The theme of the 2015 Annual Meeting of the International Society of Exposure Science-Exposures in an Evolving Environment-brought this issue to the fore. By directing attention to questions that may affect society in profound ways, exposure scientists have an opportunity to conduct "consequential science"-doing science that matters, using our tools for the greater good and to answer key policy questions, and identifying causes leading to implementation of solutions. Understanding the implications of changing exposures on public health may be one of the most consequential areas of study in which exposure scientists could currently be engaged. In this paper, we use a series of case studies to identify exposure data gaps and research paths that will enable us to capture the information necessary for understanding climate change-related human exposures and consequent health impacts. We hope that paper will focus attention on under-developed areas of exposure science that will likely have broad implications for public health.

Contributing factors to disease outbreaks associated with untreated groundwater

Disease outbreaks associated with drinking water drawn from untreated groundwater sources represent a substantial proportion (30.3%) of the 818 drinking water outbreaks reported to CDC's Waterborne Disease and Outbreak Surveillance System (WBDOSS) during 1971 to 2008. The objectives of this study were to identify underlying contributing factors, suggest improvements for data collection during outbreaks, and inform outbreak prevention efforts. Two researchers independently reviewed all qualifying outbreak reports (1971 to 2008), assigned contributing factors and abstracted additional information (e.g., cases, etiology, and water system attributes). The 248 outbreaks resulted in at least 23,478 cases of illness, 390 hospitalizations, and 13 deaths. The majority of outbreaks had an unidentified etiology (n = 135, 54.4%). When identified, the primary etiologies were hepatitis A virus (n = 21, 8.5%), Shigella spp. (n = 20, 8.1%), and Giardia intestinalis (n = 14, 5.7%). Among the 172 (69.4%) outbreaks with contributing factor data available, the leading contamination sources included human sewage (n = 57, 33.1%), animal contamination (n = 16, 9.3%), and contamination entering via the distribution system (n = 12, 7.0%). Groundwater contamination was most often facilitated by improper design, maintenance or location of the water source or nearby waste water disposal system (i.e., septic tank; n = 116, 67.4%). Other contributing factors included rapid pathogen transport through hydrogeologic formations (e.g., karst limestone; n = 45, 26.2%) and preceding heavy rainfall or flooding (n = 36, 20.9%). This analysis underscores the importance of identifying untreated groundwater system vulnerabilities through frequent inspection and routine maintenance, as recommended by protective regulations such as Environmental Protection Agency's (EPA's) Groundwater Rule, and the need for special consideration of the local hydrogeology.

Cholera epidemic associated with consumption of unsafe drinking water and street-vended water--Eastern Freetown, Sierra Leone, 2012

During 2012, Sierra Leone experienced a cholera epidemic with 22,815 reported cases and 296 deaths. We conducted a matched case-control study to assess risk factors, enrolling 49 cases and 98 controls. Stool specimens were analyzed by culture, polymerase chain reaction (PCR), and pulsed-field gel electrophoresis (PFGE). Conditional logistic regression found that consuming unsafe water (matched odds ratio [mOR]: 3.4; 95% confidence interval [CI]: 1.1, 11.0), street-vended water (mOR: 9.4; 95% CI: 2.0, 43.7), and crab (mOR: 3.3; 95% CI: 1.03, 10.6) were significant risk factors for cholera infection. Of 30 stool specimens, 13 (43%) showed PCR evidence of toxigenic Vibrio cholerae O1. Six specimens yielded isolates of V. cholerae O1, El Tor; PFGE identified a pattern previously observed in seven countries. We recommended ensuring the quality of improved water sources, promoting household chlorination, and educating street vendors on water handling practices.

Formaldehyde levels in FEMA-supplied travel trailers, park models, and mobile homes in Louisiana and Mississippi

In 2006, area physicians reported increases in upper respiratory symptoms in patients living in U.S. Federal Emergency Management Agency (FEMA)-supplied trailers following Hurricanes Katrina and Rita. One potential etiology to explain their symptoms included formaldehyde; however, formaldehyde levels in these occupied trailers were unknown. The objectives of our study were to identify formaldehyde levels in occupied trailers and to determine factors or characteristics of occupied trailers that could affect formaldehyde levels. A disproportionate random sample of 519 FEMA-supplied trailers was identified in Louisiana and Mississippi in November 2007. We collected and tested an air sample from each trailer for formaldehyde levels and administered a survey. Formaldehyde levels among all trailers in this study ranged from 3 parts per billion (ppb) to 590 ppb, with a geometric mean (GM) of 77 ppb [95% confidence interval (CI): 70-85; range: 3-590 ppb]. There were statistically significant differences in formaldehyde levels between trailer types (P < 0.01). The GM formaldehyde level was 81 ppb (95% CI: 72-92) among travel trailers (N = 360), 57 ppb (95% CI: 49-65) among mobile homes (N = 57), and 44 ppb (95% CI: 38-53) among park models (N = 44). Among travel trailers, formaldehyde levels varied significantly by brand. While formaldehyde levels varied by trailer type, all types tested had some levels ≥ 100 ppb.

Economic and health impacts associated with a Salmonella Typhimurium drinking water outbreak-Alamosa, CO, 2008

In 2008, a large Salmonella outbreak caused by contamination of the municipal drinking water supply occurred in Alamosa, Colorado. The objectives of this assessment were to determine the full economic costs associated with the outbreak and the long-term health impacts on the community of Alamosa. We conducted a postal survey of City of Alamosa (2008 population: 8,746) households and businesses, and conducted in-depth interviews with local, state, and nongovernmental agencies, and City of Alamosa healthcare facilities and schools to assess the economic and long-term health impacts of the outbreak. Twenty-one percent of household survey respondents (n = 369/1,732) reported diarrheal illness during the outbreak. Of those, 29% (n = 108) reported experiencing potential long-term health consequences. Most households (n = 699/771, 91%) reported municipal water as their main drinking water source at home before the outbreak; afterwards, only 30% (n = 233) drank unfiltered municipal tap water. The outbreak’s estimated total cost to residents and businesses of Alamosa using a Monte Carlo simulation model (10,000 iterations) was approximately $1.5 million dollars (range: $196,677–$6,002,879), and rose to $2.6 million dollars (range: $1,123,471–$7,792,973) with the inclusion of outbreak response costs to local, state and nongovernmental agencies and City of Alamosa healthcare facilities and schools. This investigation documents the significant economic and health impacts associated with waterborne disease outbreaks and highlights the potential for loss of trust in public water systems following such outbreaks.

Surveillance for waterborne disease outbreaks associated with drinking water---United States, 2007--2008

PROBLEM/CONDITION

Since 1971, CDC, the Environmental Protection Agency (EPA), and the Council of State and Territorial Epidemiologists have collaborated on the Waterborne Disease and Outbreak Surveillance System (WBDOSS) for collecting and reporting data related to occurrences and causes of waterborne disease outbreaks associated with drinking water. This surveillance system is the primary source of data concerning the scope and health effects of waterborne disease outbreaks in the United States.

REPORTING PERIOD

Data presented summarize 48 outbreaks that occurred during January 2007--December 2008 and 70 previously unreported outbreaks.

DESCRIPTION OF SYSTEM

WBDOSS includes data on outbreaks associated with drinking water, recreational water, water not intended for drinking (WNID) (excluding recreational water), and water use of unknown intent (WUI). Public health agencies in the states, U.S. territories, localities, and Freely Associated States are primarily responsible for detecting and investigating outbreaks and reporting them voluntarily to CDC by a standard form. Only data on outbreaks associated with drinking water, WNID (excluding recreational water), and WUI are summarized in this report. Outbreaks associated with recreational water are reported separately.

RESULTS

A total of 24 states and Puerto Rico reported 48 outbreaks that occurred during 2007--2008. Of these 48 outbreaks, 36 were associated with drinking water, eight with WNID, and four with WUI. The 36 drinking water--associated outbreaks caused illness among at least 4,128 persons and were linked to three deaths. Etiologic agents were identified in 32 (88.9%) of the 36 drinking water--associated outbreaks; 21 (58.3%) outbreaks were associated with bacteria, five (13.9%) with viruses, three (8.3%) with parasites, one (2.8%) with a chemical, one (2.8%) with both bacteria and viruses, and one (2.8%) with both bacteria and parasites. Four outbreaks (11.1%) had unidentified etiologies. Of the 36 drinking water--associated outbreaks, 22 (61.1%) were outbreaks of acute gastrointestinal illness (AGI), 12 (33.3%) were outbreaks of acute respiratory illness (ARI), one (2.8%) was an outbreak associated with skin irritation, and one (2.8%) was an outbreak of hepatitis. All outbreaks of ARI were caused by Legionella spp. A total of 37 deficiencies were identified in the 36 outbreaks associated with drinking water. Of the 37 deficiencies, 22 (59.5%) involved contamination at or in the source water, treatment facility, or distribution system; 13 (35.1%) occurred at points not under the jurisdiction of a water utility; and two (5.4%) had unknown/insufficient deficiency information. Among the 21 outbreaks associated with source water, treatment, or distribution system deficiencies, 13 (61.9%) were associated with untreated ground water, six (28.6%) with treatment deficiencies, one (4.8%) with a distribution system deficiency, and one (4.8%) with both a treatment and a distribution system deficiency. No outbreaks were associated with untreated surface water. Of the 21 outbreaks, 16 (76.2%) occurred in public water systems (drinking water systems under the jurisdiction of EPA regulations and water utility management), and five (23.8%) outbreaks occurred in individual systems (all of which were associated with untreated ground water). Among the 13 outbreaks with deficiencies not under the jurisdiction of a water system, 12 (92.3%) were associated with the growth of Legionella spp. in the drinking water system, and one (7.7%) was associated with a plumbing deficiency. In the two outbreaks with unknown deficiencies, one was associated with a public water supply, and the other was associated with commercially bottled water. The 70 previously unreported outbreaks included 69 Legionella outbreaks during 1973--2000 that were not reportable previously to WBDOSS and one previously unreported outbreak from 2002.

INTERPRETATION

More than half of the drinking water--associated outbreaks reported during the 2007--2008 surveillance period were associated with untreated or inadequately treated ground water, indicating that contamination of ground water remains a public health problem. The majority of these outbreaks occurred in public water systems that are subject to EPA's new Ground Water Rule (GWR), which requires the majority of community water systems to complete initial sanitary surveys by 2012. The GWR focuses on identification of deficiencies, protection of wells and springs from contamination, and providing disinfection when necessary to protect against bacterial and viral agents. In addition, several drinking water--associated outbreaks that were related to contaminated ground water appeared to occur in systems that were potentially under the influence of surface water. Future efforts to collect data systematically on contributing factors associated with drinking water outbreaks and deficiencies, including identification of ground water under the direct influence of surface water and the criteria used for their classification, would be useful to better assess risks associated with ground water. During 2007--2008, Legionella was the most frequently reported etiology among drinking water--associated outbreaks, following the pattern observed since it was first included in WBDOSS in 2001. However, six (50%) of the 12 drinking water--associated Legionella outbreaks were reported from one state, highlighting the substantial variance in outbreak detection and reporting across states and territories. The addition of published and CDC-investigated legionellosis outbreaks to the WBDOSS database clarifies that Legionella is not a new public health issue. During 2009, Legionella was added to EPA's Contaminant Candidate List for the first time.

PUBLIC HEALTH ACTIONS

CDC and EPA use WBDOSS surveillance data to identify the types of etiologic agents, deficiencies, water systems, and sources associated with waterborne disease outbreaks and to evaluate the adequacy of current technologies and practices for providing safe drinking water. Surveillance data also are used to establish research priorities, which can lead to improved water quality regulation development. Approximately two thirds of the outbreaks associated with untreated ground water reported during the 2007--2008 surveillance period occurred in public water systems. When fully implemented, the GWR that was promulgated in 2006 is expected to result in decreases in ground water outbreaks, similar to the decreases observed in surface water outbreaks after enactment of the Surface Water Treatment Rule in 1974 and its subsequent amendments. One third of drinking water--associated outbreaks occurred in building premise plumbing systems outside the jurisdiction of water utility management and EPA regulations; Legionella spp. accounted for >90% of these outbreaks, indicating that greater attention is needed to reduce the risk for legionellosis in building plumbing systems. Finally, a large communitywide drinking water outbreak occurred in 2008 in a public water system associated with a distribution system deficiency, underscoring the importance of maintaining and upgrading drinking water distribution system infrastructure to provide safe water and protect public health.

Assessing the roles of temperature, precipitation, and ENSO in dengue re-emergence on the Texas-Mexico border region

OBJECTIVE

The goal of this study was to assess linkages between microclimate and longer-term ENSO-related weather forcing on the week-to-week changes in dengue prevalence in Matamoros, Tamaulipas, Mexico, over a recent decade of dengue observations.

MATERIAL AND METHODS

An auto-regressive model to evaluate the role of climatic factors (sea-surface temperature) and weather (maximum temperature, minimum temperature, precipitation) on dengue incidence over the period 1995-2005, was developed by conducting time-series analysis.

RESULTS

Dengue incidence increased by 2.6% (95% CI: 0.2-5.1) one week after every 1 degree Celsius increase in weekly maximum temperature and increased 1.9% (95% CI: -0.1-3.9) two weeks after every 1 cm increase in weekly precipitation. Every 1 masculineC increase in sea surface temperatures (El Niño region 3.4 ) was followed by a 19.4% (95% CI: -4.7-43.5) increase in dengue incidence (18 weeks later).

CONCLUSIONS

Climate and weather factors play a small but significant role in dengue transmission in Matamoros, Mexico. This study may provide baseline information for identifying potential longer-term effects of global climate change on dengue expected in the coming decades. To our knowledge, this is the first study to investigate the potential associations between climate and weather events and dengue incidence in this geographical area.

Epidemic dengue and dengue hemorrhagic fever at the Texas-Mexico border: results of a household-based seroepidemiologic survey, December 2005

A dengue-2 epidemic causing dengue hemorrhagic fever (DHF) occurred in the contiguous border cities of Matamoros, Tamaulipas (Mexico), and Brownsville, TX, in 2005. In December, we conducted a household-based epidemiologic survey to determine the incidence and seroprevalence of dengue infection among Matamoros and Brownsville residents and to identify risk factors associated with infection. Antibodies to dengue were measured in 273 individuals. The estimated incidence of recent dengue infection was 32% and 4% among Matamoros and Brownsville participants, respectively. The estimated prevalence of past dengue infection was 77% and 39% among Matamoros and Brownsville participants, respectively. The Breteau index was 28 in Matamoros and 16 in Brownsville, reflecting an abundant winter population of Aedes mosquitoes. Discarded waste tires and buckets were the two largest categories of infested containers found in both cities. Our results underscore the risk for epidemic dengue and DHF in the Texas-Mexico border region.